For those who have questions about CPD and RCS, I have only had mine about 3 weeks. I started with 9 CPD and 40 RCS. In the time I have had them the CPD have managed to consume all but a few of the RCS, and not just the small ones. Some of the biggest ones were actually the first to go. I cant explain this as what I have read said the large shrimp would not be bothered. As of now I can only spot 1 lone shrimp. I suspect there may be another one or two hiding deep in the plants.